Synthetic rubber and process of its manufacture



, Patented Apr. it, 1953 .hard rubber.

never reached the commercial stage except .for a brief period during therecent war, the material being unsatisfactory as regards both attestsWILLIAM s CALCOTT, orjrmms snow-3," nnnnnmox B. nowmne, or cAmgnYsrom'r,

AND DONALD E. POWERS, OF EENNSI GROVE, NEW. J'EBSEYjASSIGNO BS TO E. I.

DU EON! DE NEMOUBS & COMPANY, OF WILMINGTON, DELAWARE, A COBPORA TION OBDELAWARE RUBBER AND PROCESS OF ITS MANUFACTURE r i No Drawing'theMprocess hereinafter described in detail.

ch work has been done in the past onthe synthesis of rubber-likemater'als by the polymerization of hydrocarbons? Due to the nature ofthe processes employed in their production the resulting products werewhol- 1y unsuitable for soft rubber spbstitutes, though satisfactory toa certain, extent for Synthetic rubber therefore properties and price. w

The object of this invention is to produce synthetic or partiallysynthetic rubber-like materials of sufficiently low price and highquality to be marketable.

Among the numerous advantages of 'the products of the new process overprior products of this type is the fact that, while the prior methodsgave products of little elasticity, difiicult or impossible to mill,curable to hard rubber with difiicult and entirely unsuitable for softrubber, t is. process gives a productof high elasticity, easily milledand workable by the usual methods and machinery used for rubber, andsuitable for the soft or elastic type of rubber goods as well as thehard. Physically, the product differs from the materials previouslyproduced in that it possesses a definite structure resembling that ofrubber instead of being merely a colloidal solution of polymers in eachother.

The process also represents a fundamental improvement over the prior artas regards the number of steps between the raw material and finishedarticle.

Application filed August 12, 1927. Serial No. 212,605.

form.

sass;

structure similar to, if not identical with, I

the divinylacetylenes and the reduction roducts obtaind by thehydrogenation o the vinyl and divinyl .acetylenes- More generally it maybe stated that a given hydrocarbon can be satisfactorily employed inthis synthesis provided it be a liquid or gas at normal roomtemperatures, and'polymerizable to a more ,viscous liquid from which thepolymer does not separate in crystalline possible to stop, or slow up tothe practical equivalent of stopping, the polymerization at the desiredpomt.

A still further property requisite for the is that the hydrocarbonpolymers when heated with sulfur and a catalyst (accelerator) togetherwith the usual compounding ingredients, shall yield more viscous or lessliquid products, thus permitting a cure of.

the raw rubber. This is a eneral property of. the hydrocarbons name andis also essential to the success of the operation.

' These conditions are met by a wide variety of hydrocarbons, such asthose mentioned hydrocarbons to be used for this synthesis.

A further conditlon is that it must be 'above including under each groupthe corf product from such, hydrocarbons may be briefly outlined inprinciple as follows, in- ;iividual steps being discussed in more detailater.

. A polymerizable hydrocarbon as set forth above is thoroughlyemulsified with water or any other suitabl liquid and certain importantaccessor substances, to be described more portion arly hereinafter, toan emulgg H H 1 9933 5 30,

10211 0i grain sizesimiiar to that zet natural 1 :cal: ires'ins:posse'ssin :these' p'rbp'eftieq K 'eeated t 2202': approixiiniat' adiam tur r thesfenhta inedifreirntreas red guayule micifilb itheemuisifiecl; y rabtertyex iraeeoa with emote; i then: be polymerizedunder: eonditiens; tion' :ofa' r esinous constituent of th sgtype is atease a mere; detainees; saint tend was rer important tepl its'presencenrireisthe: being: adapted i te% iestablish :the' emaaimu desiredpiastieity u iviseosityiintbe iextern' st i ingth andelastieityef:theenagunm to be or continuous :paae read: is: also: atte}t obtaineddater The resulting :emulsien at the deaelepment :ef the strenpolyerizied hydrecarb on: is then eeagulated 1 by: any set:theeimlethods: erdiaarily zempipy ed are thezcoagulation: or n tural-leafter:

r; a plurality; sf. substances:

inshellac, agar-agar, or,

1 & mi ing an ea i g by likebodies afr ebta ed,

. rubber repertie 2v ryiin g rwa 1th roearbou. -d, th;efiegrpolymerization, and the; nature :an

amount: :of; :the aee'essery: substances; addedduring emulsifieationetci; v v v The ae esserysubstancesmentioned aboiv Thesetwafmietiensma 1tedby:thesamezieorapcundgtcr ex ample, hydrophiiic; proteins :as egg;albums fht he added,

onder more; iendingehi eireulsiitgyi n cues, the: remainder ea a e th;

gelat' case or alkali soluble proteins are satisfactory protectlveagents. Water soluble proteins when used may function also as collectingagents and thereby much simplify subsequent operations by eliminatingthe necessity of mechamcal collection or aggregation of the preclpitateor coagulum. The precise method or agents employed for efi'ectingemulsificationis, however, not important, as any of the establishedmethods of preparing stable emulsions of hydrocarbons in water may beemployed.

In addition to the substances used for the pre aration and stabilizationof the emulsion of t e hydrocarbon, to build up the desired rubber-likestructure, it is preferred to add a water insoluble resinous body of arelatively soft and plastic or viscous nature, which body must bechemically of such a type as to re- 65 range 3 to 10 in the presence ofwater. Typip p p this ease-taaad aesaitqae' in general, Water table:resins; which water: ruse en up and; utilized by: th h ether miuisie i1resin which will still further improve the quality of the finishedproduct. Where the term resinous substance or resinous constituent isemployed hereinafter it is to be understood to refer generically toisolated amorphous bodies of ill defined or indefinite melting pointwhich bodies are of the type describedabove, including substances whichwill be precipitated in the form of such amorphous bodies under theconditions of coagulation, as well as to mixtures containin such "resinsin unisolated form.

incethe hydrocarbons concerned in the process are highly unsaturated andconsequently susceptible to oxidation, it is deslrable to alsoincorporate in the emulsion one of the Well-known rubber antioxidants inorder to preclude oxidation of the coagulum to be obtained. It is alsodesirable, although not'essential, toincorporate one of the rub-- bervulcanization accelerators, although this is of very minor importance ascompared with the other substances. The amount of such substances to beemployed will of course be varied according to the substances emplgyed npreparing the emulsion, a mixer or a rotating agitator may be employedand it is preferable to agitate violently for sometime to reduce thesize of the particles of soiuble in water or very weakly alkaline aqua;

synthetic rubber.

hydrocarbon to substantially that of the particles present in Hevealatex or approx!- imately-to 1 micron in diameter. Substantial deviationin either direction from this particle' size will materially reduceeither the tensile strengthor the elasticity of the desirable that theparticle size be held as closely as possible to an average of 1 micronand also that thepercentage "of very, large and very small particles beheld very low.

The polymerization of the fluid hydrocarbon may be partially effectedbefore emulsification and then carried on to the desired point or itmaybe emulsified without substantial polymerization and all the desiredpolymerization carried out subsequently to the emulsification. Any ofthe well known methods for efiecting polymerization may bon"'may beallowed to stand exposed to the air until-the desired condition isreached or it may be maintained at a suitabletemperature, generallyabove-normal, to accelerate the reaction, oi. a catalyst such as anoxidizing agent or anaromatic sulphonic acid may be employed in.addition to heating.

The use of ultra violet light is also a well.

known method of effecting polymerization of substances of the type ofisoprene. The particular manner and conditions of efi'ecting thepolymerizationare immaterial for the purposes of the present .invention.After polymerization has been carried to the desired point, the emulsionis coagulated to obtain the rubber-like product.

The invention having been described above as applicable to polymerizablehydrocarbons in general, it will now be described with more particularreference to preferred embodiment which involves tile use of the.reduction products of polymers preared from acetylene. It is to be understood that the following description is mere-.

ly illustrative of the manner of applying the process to polymerizablehydrocarbons in general.

The first step in this embodiment is the preparation, from acetylene,boiling polymers. Themethod of producing these particular polymers,however, is not a but is the subject of part of this invention It may beseparate patent applications. stated here, however, formof thisreaction, polymerization is ,carried out by treating with acetylene, ata temperature preferably not substantially over 30 0., a suspension ofcuprou'schloride and .ammonium chloridein water 'andi ofithe resultingproduct. Any quprous' s alt however, for example. copper sulphate,-.and

distilling other alkali chlorides as'sodium or potassium chloride may beused'instead of the mixture of cuprous chloride and ammonium chloride,the essential requirement being that at least It is therefore obviouslyposing the complexes formed be employed. The hydrocar-.-

to a viscous of the higher that in the preferred a small amount of thecuprous salt be solution, possess an acid or neutral,but not analkaline, reaction. The polymers of acetylene, so ob-. tained, may berecovered from-thecatalyst by several methods, as for instance bydecomby means of acids, cyanides, or ammonia, or by simply heating anddistilling off the polymers ,at atmospheric or reduced pressure, or bysolvent extraction, 'or other obvious. methods. In the preferred methodof effecting polymerization given 'above,,the polymer recovered ischiefly divinylacetylene, having the struc-' turalformula H C CH C E CHC =7 CH but other polymers may be, and probably are, formed in greatamounts under varying conditions. Evidence of the existence of one ofthese, found, and others might be shown to exist,

but the precise structure of these hydrocarbons is immaterial for thepurposes of this invention.

tion, and is the subject of separate patent applications. 1

'The hydrocarbon thus obtained by the cuprous salt reaction may processor alternatively it may be partially reduced with, for in stance,hydrogen and a catalyst, before incorporation into the emulsion. Thedegree of hydrogenation may vary,

the criterion being that the hydrocarbon ob- 'tained must still possessthe ability to polymerize.

Palladium, platinum, nickel, copper, or iron maybe employed as thecatalyst, with or without a promoter. A satisfactory hydrogen ratio mayapproximate 1 and that the'reaction mass should methylenepentamethylene, has been hydroquinone, acetbe employed in the moles ofhydrogen to 1 mole of acetylene polymer but this ratio maybe varied atwill, bearing in mind, however, that if the hydrogenation is, carriedtoo far theproducts will not be polymers izable. The temperature (shouldbe kept as y h low as po'ssible to avoid polymerization ofthedivinylacetylene in the catalyst chamber.

Diluents may be added tothe gas reaction mass to facilitate temperaturecontrol; any substance which is non-reducible and gaseous at thereaction temperature (saturated aliphatic hydrocarbons,'aromatic andhydroaromatic hydrocarbons, water, fatty acids,

.1 for instance,:maybe'recoveredbyforining f j i i f the SOderivative,the-olefinesbytheiormae j i I Ofthsulphuricacidaddition'compound,

' the acetylene .delivatiyes, by :means of the:

omplex,-: ae+

I; methods indicated aboveisready foremulsi-= .fication and furtherpolymerization: and sub i f be suspended in 21.50% alcohol, 50% wateralcohols) may be added. 1 Alternatively, the catalyst. may. be Suspendedin: the hydrocar': bon, preferably in the presence of a solvent, and thereduction carried out in the liquid phase. For; example, pailadium blackmay solution ofthehydrocarbon, and hydrogen passed in at 40 C. -Rapidreduction takes place; It j desired, the vigor of the vaporphasereduction may be reduced by working :under reduced pressure,whiletheliquid" phasereactioncan be carried outunderin creasedpressureto speed; up the reaction: it

desired Reducingthe pressure also reduces p Example 1.- Aftertheaddition of the resin ous constituent,polymerizationis carried out byheating'to C. for *6 months; After thepolymerization.during; reduction.-5

The reaction-prod c a mixture. of the-original hydrocarbon, ,firiene d ses-d e dp rafiin hydroe The; mixed reduction product or its carbon maybe Separated by fractionaldist-illation or by chemicaltreatment. Thedi'enes,

cuprous ammonium chloride .0 .cordingto known methods.

rated constituents obtained by any of the Q i i i I n i p p p i p i z Isequent coagulationto obtain the finalprod- 5 described in connectionwithhydrocarbons in not as already described in connection withhydrocarbons generallm; 'lhe polymerization maybe effected any ofthemeithods already general. A suitable degree ofp'olymerization isattained When approximately 25% of the hydrocarbon is insoluble inbenzene. Coagulation is then efi'ected to produce the rubberlike body.

In order to better disclose the invention, specific examples of theapplication of the process to particular hydrocarbons are furn shedbelow. It is to be understood, of course, that these examples are merelyillustrative of the method already described as adapted for thetreatment of polymerizable hydrocarbons generally.

Example 1.To 100 parts of divinylacetylene obtained by thepolymerization of acetylene there are added 200 parts of water, 2 partsof naphthenic acid sodium salts, and 1 part of gelatin. The mixture isagitated violently until it is found upon microscopic examination thatthe average particle size is l-micron and that disproportionably largeor small particles are chiefly absent. With this emulsion there is thenmixed 1 part of guayule resin. in the form of an aqueous suspension. Themixture is then allowed to stand for 7 days at room temperature (25 C.)to polym gentle agitation. Two-tenths of a part of hydroquinone in theform of an aqueous soluis "freed from Water b conta n ng probably:

- polymerization, theprocess is carried set forth'in Example 1'.

- Example rte-An emulsion is prepared as indicated in Example 1 but fromthe mixture of hydrocarbons rcsultingfro ni the-reduction ofdivinylacetylene with l /gmoles'ofhydro sep a polymerizatiom under theconditions outli above, oil :4 dimejthyl butadiene, a reduction productof divinylacetylene, the emulsion preaeeaaoo hated by the addition ofsufiicient 2% acetic acid'to change the: pH-of the solutiontoapproximately 4.. The eoagulum thus obtained y milling and is ready foruse asraw-rubber.- I s j s p s Example 2.-San1e as 1 except that therubber latex; is omitted and the guayule resin acetylene.

is increased to 3 parts per 100' of 1' divinyli i 1 EmampZe3.+-l -o 100parts of1:4d methyl butadiene obtained, as already described,

not the reduction products of: divinylacetylene an emulsion is preparedas indicated in i j gen as descrl ed above. The emulsion iis then mixedwith 25% i eeneenmted formic -ac-idsolution and heated to C. for onegelatinous polymer is: formed, in-

D'IOIltlL: A solublein alcohol. i I

i It will be noticed that Where other hydro i ployed,th'e timereqriiredfor effecting poiym i i 3 generallybe very materially inis f iFor i example, to effect complete i nc d' carbons than acetylenepolymers are; em-

eriz'a-t' on will creased.

pared from this hydrocarbon is maintained at 25 C. for about six months.Otherwise the procedure is substantially in accordance With thatdescribed for divinylacetylene.

outas The emulsion prior to coagulation strikv 'ingly resembles naturallatex in its physical structure and properties. It is a two phase systemcontaining hydrocarbon droplets as the disperse phase. The droplets ofpolymerized-hydrocarbon are of uniform sze ap proximating a diameter of1 micron and are suspended in a continuous phase comprising,

like natural latex, a resinous constituent. D e to the polymerization ofthe hydrocarbon in an emulsified state these droplets are made up ofhydrocarbon spheroids encased n a layer of more viscous and more highlypolymerized hydrocarbon.

lihe synthetic substances obtained by coagulation of such an emulsion asdescribed exhibit to an unusual degree all the characteristics ofnatural rubber.

The resulting coagulum will vary in properties in accordance w th theoptional method used for its preparation, as Well as with the extent toWhichthe hydrocarbon has been polymerized before coagulation. Roughly,the fresh eoagulum varies from the consistency of badly swelled freshlycoagulated diffraction pattern, obtained upon taking an I aches latex tothat of normal coagulated latex,

while after dryin it varies rom softened crepe rubber to no a1 creperubber. Under polymerization it will give a product reseml1n overmilled'ore e.

Tl ie material prodbced by this process can be readily distinguishedfrom previously prepared synthetic rubbers,by the fact that the X-rayphotograph of the stretched material, s closely similar to that obtainedfrom natural rubber, and is that ordinarily con- 1 sideredcharacteristic of a crystallme body{ whereas the corresponding potographs o the other synthetic rubbers are characteristic of anamorphous body. vIn our opinion, this diffraction pattern is notnecessarily indicative of a crystalline substance, but only of asubstance in which themolecules possess definite orientation, although1t has been commonly accepted in the past as evidence of crystallinity.

. According to our working hypothesis, the material produced by thisprocess consists essentially of a 2-phase liquid system. The-in-' ner,or disperse, phase consists of small particles or globules,aplproximately 1 micron in diameter, compose of partially polymerizedhydrocarbon, the'degree of polymerization decreasing globules, or, inother words, the higher polymer' tending to concentrate in the interface between the two phases. The external hase consists of a highlyviscous liquid or p astic solid, completelffilling' the capillary spacesbetween the globules, and these spaces be tween globules at no pointexceed capillary dimensions. The external phase may be composed eitherof a resin, amixture of a resin with a higher polymer of thehydrocarbon, or of the higher polymer only, and it is not essential thatthere be a clean-cut sharp diyid ing line between the two phases.

The finished product may be treated in the same general manner as rawrubber. It may i be milled, the usual chemicals such as zinc oxide,sulfur, accelerators, carbon black softeners, antioxidants, etc.,incorporated. It can be cured, or vulcanized, by heat treatment appliedin a manner similar to that 'usedincuring natural rubber. It can also-becured with sulfur chloride, or, in general, by the methods and reagentsused for natural rub- 55. ber. 7 The precise methods used form no Jwidenumber of variations. The fundamen-. tal property common to all of theproducts marked degree, eloigations of u toward the center of the madeaccording to the procedure described -is that of elasticity. All of thematerials produced, suitably cured, possess elasticity to a having beenobtain The tensi e strength varies withthe precise mode of preparation,

the hydrocarbon or hydrocarbons used, and. the degree of pol in thefactors just mentioned.

e materials thus prepared ma be used tex and as a general substitute fornatural natural rubber.

We claim: v

1. The process of making a synthetic rub her-like material from apolymerizable hydrocarbon which comprises coagulating an emulsion of apolymerizable hydrocarbon,

said emulsion containing a resinous constituent. a

2. The

erization. The other 1 properties can also e varied widely byvaryprocess of making a rubber-like material from polymerizablehydrocarbons which comprises forming an aqueous emulsion, containin thepolymerized hydrocarbon, the emulsified particles'of hydrocarbon beingsubstantially the size of the particles present in Hevea latex, andcoagulating said emulsion. 1

- 3. The process of making a latex-like emulsion of a polymerizablehydrocarbon,

saidi emulsion containing a resinous constituen r I g r 4. The processof making a latex-like liquid which comprises preparinga-nnxture of aresinous constituent m an aqueous emu sion of a'polymerizablehydrocarbon, the

emulsified particles of hydrocarbon having a diameter of substantially 1micron.

'5. The process of making a rubber-like material which comprises@forming an aqueous emulsion contaminga polymerizable hydrocarbon andaresinous substance-in. which emulsion the particles of hydrocarbonhave. substantially the size of the particles present in natural latex,polymerizing the emulsified hydrocarbon and, coagulating.

6. The process set forth in claim 5 in which the resinous substancecomprises/a mixture of-gu'ayule resin andnatural latex.

. 7.. The process of .m'aking a rubber-like material which comprisesmixing a poly.- merizable hydrocarbon with water, an emulsifying'agentand a protective colloid, agitating said mixture until the averageparticle "size of the hydrocarbon is substantially 1 micron,incorporating with the resulting emulsion an aqueous suspensionof aresinous constituent, effecting polymerization of. the emulsified,hyd'rocarbons, incorporating an antioxidant to efiect stabilization andcoagulating.

8. In the process of making a rubber-like material the step whichcomprises polymerliquid which comprises preparing an aqueous 9 v izingthe reduction products of divinylacetylene.

9. The process of making a latex-like liquid which comprises'forming anemulsion of a polymerizable reduction product of divinylacetylene.

10. The process of making a rubber-like material which comprisescoagulating an emulsion of a polymerized reduction product ofdivinylacetylene. I

11.. The process of making a rubber-like material which comprises mixinga pel merizable reduction product of divinylacetylene with water, anemulsifying agent and a protective colloid, agitating said mixture untilthe. average particle size of the hydro carbon is substantially 1micron, incorporating with the resulting emulsion an aqueous suspensionoi a resinous constituent, effecting polymerization of the emulsifiedhydrocarbons, incorporating an antioxidant to efiect stabilization andcoagulating.

12. A synthetic latex-like liquid compris-' ing an emulsion of apolymerized hydrocarbon, the emulsified particles of said hydrocarbonhaving a .size substantially corresponding to the size of the particlespresent in Hevea-latex.

13.A synthetic latex-like liquid comprising an emulsion of apolymerizable hydrocar-.

bon, in admixture with a resinous constituent.

14. A synthetic latex-like liquid comprising an emulsion of apolymerizable hydrocar hon, in admixture with a resinous constituent,the emulsified particles of said hydrocarbon ing progressively lesspolymerized from their surfaces inwardly and having a size agulatingsaid emulsion.

18. latex-like product resulting from preparing a mixture of a resinousconstituent in an aqueous emulsion of-a polymerizable hydrocarbon, theemulsified tially 1 micron..

particles of hydrocarbon having a diameter of substanaqueous emulsion ofa polymer- 19. A rubber-like product resulting from" forming an aqueousemulsion containing a polymerized hydrocarbon and a resinous substance,in which emulsion the particles of i which the external aeoatoohydrocarbon have substantially the size of the particles presentinnatural latex, and coagulating. A

20. A rubber-like product resulting from forming an aqueous emulsioncontaining a polymerizable hydrocarbon and a resinous substancecomprising a mixture of guayule resin and natural latex, in whichemulsion the particles of hydrocarbon'have substantially the sizeof theparticles present in natural latex, polymerizing the emulsifiedhydrocarbon and coagulating.

21. A rubber-like material comprising the polymerized reduction productsof divinylacetylene.

22. A rubber-like product resulting from forming an aqueous emulsioncontaining a polymerizable reduction product of divinylacetylene and aresinous substance, in which emulsion the particles of hydrocarbon havesubstantially the size of the particles present in natural latex,polymerizing the emulsified reduction product and coagulating.

23. lA'synthetic rubber-like material showing, under the X-ray adifi'raction pattern of the type ordinarily considered characteristic ofa crystalline body.

24. A rubber-like product comprising a 2- phase system, the dispersephase comprising particles of a polymerized reduction product of.divinylacetylene and the external phase comprising a viscous liquid orplastic solid.

25. A rubber-like productcomprising a 2- phase emulsoid system, thedisperse phase comprising particles of polymerized hydrocarbon, thedegree of polymerization decreasing toward the center of said particles,and the external phase comprising a viscous liquid or plastic solid,said system showing, under the Xray, a difl'raction pattern of the typeordinarily considered characteristic of a crystalline body.

26. The product set forth in claim 25 in phase comprises a resinousconstituent.

27. The process of making a synthetic rub bur-like material from apolymerizable hydrocarbon which comprises coagulating an emulsion of thepolymerized hydrocarbon,

said emulsion containing a resinous constit-' Iient and a water solubleprotein.

28. The process of'making a rubber-like material which comprisescoagulating an emulsion of a polymerized reduction product ofdivinylacetylene and a Water soluble protein. i

29. A synthetic rubber-like product resulting from coagulating anemulsion of a polymerized hydrocarbon, said emulsion containing aresinous constituent anda water soluble protein.

30. A rubber-like product resulting from coagulatingan emulsioncomprising the polymerized reduction products-ofdivinylacetypolymerizing.

hydrocarbons, and coagulating. I

35. A rubber-like material comprising the polymerized reduction productsof a polyaecasce lcne, a resinous constituent and a water solubleprotein.

31. In the process of making a rubber: like material, the steps whichcomprise polymerizing a reduction product of a polymeriz-' polymerizablereduction product of a polymerizable acetylene polymer, agitating saidemulsion until the average particle size of the hydrocarbon issubstantially 1 micron, incorporating with the resulting emulsion anaueous suspension of a resinous constituent,

e ectmg polymerlzatlon of the emulsified merizable acetylene polymer.

36. A rubber-like product resulting from formirig an aqueous emulsioncontaining a polymerizable reduction product of apolymerizable'acetylene polymer and a resinous substance, in whichemulsion the particles of hydrocarbon have substantially the size of theparticles present in natural latex, poly- (1.3' isoprene and2.3-dimethylhutadienein emulsion with water and an emulsiying agent thestep which comprises homogenizing the emulsion before polymerizing.

tures.

merizing the emulsified re'duction product,

and coagulating.

37. A. rubber-like product obtainable by coagulating an emulsioncomprising a polymerized reduction product of a polymerizable acetylenepolymer, a resinous constituent and a water soluble protein.

38. A rubber-like product obtainable by emulsifying apolymerizablereduction product of a polymerizable acetylene polymer,agitating said emulsion until the average particle size of thehydrocarbon is substantially 1 micron, incorporating with the re sultingemulsion an agueous suspension of a resinous constituent, efiectingpolymerization of the emulsified hydrocarbon, and co agulating.

39. The process of making a latex-like liquid which comprises forminganemulsion of a resinous substance and a polymerizable reduction productofa polymerizable acety lene polym'er andthereafter polymerizing theemulsified reduction product.

40. In the process of polymerizing a butadiene hydrocarbon in emulsionwith waterand an emulsifying agent, the step which compriseshomogenizing the emulsion before 41. In the process of polymerizing acompound of the group consisting of butadienewnirrnn s. cALoo rr;rnnnnnrcn n. nownnre.

' DONALD n. rownns:

In testimony whereof we a our signa-

